1. Field of the Invention
The present invention relates to a cooking device such as a microwave oven and, more particularly, to a cooking device capable of mixing heat generated as cooking or pyrolysis cleaning is performed in a cooking chamber with external cold air sucked to an electronic equipment chamber and discharging cooled air when its door is opened following the cooking or pyrolysis cleaning.
2. Description of the Related Art
FIG. 1 is a partially cut perspective view of a cooking device in accordance with a related art, FIG. 2 is a side sectional view of the cooking device with its door closed in accordance with the related art, and FIG. 3 is a side sectional view of the cooking device when its door is opened in accordance with the related art.
The cooking device as shown in FIGS. 1 to 3 includes a cabinet 1, a cooking chamber 2 provided in the cabinet 1 and is heated to perform cooking on a food item, a door 7 installed at a front side of the cabinet 1 and opening and closing the cooking chamber 2, an electronic equipment chamber 3 positioned at an upper space of the cooking chamber 2 in the cabinet 3, and a blower 4 for cooling electronic components or the like inside the electronic equipment chamber 3.
The cooking chamber 2 is heated by an electric heater 2′ or a burner and the like.
The blower 4 forms a self-cooking passage under the condition of high temperature generated when cooking or pyrolysis cleaning is performed, and generally includes a fan 5 and a fan motor 6 for driving the fan 5.
As indicated by arrows in FIG. 2, during cooking or pyrolysis cleaning, the blower 4 installed at a rear side in the electronic equipment chamber 3 sucks to supply external cold air to the electronic equipment chamber 3 through a space positioned at a lower portion of the cooking chamber 2 and then a space positioned at a rear portion of the cooking chamber 2, and discharges heat present in the electronic equipment chamber 3 to a front side of the cooking chamber 2 where the door 7 is positioned, thereby cooling air in the electronic equipment chamber 3.
Since the door 7 is directly heated by heat radiated and convected inside the cooking chamber 2, a cooling passage 7′ is formed therein to prevent a user from being burned.
Regarding the cooling passage 7′ of the door 7, when air is discharged from the electronic equipment chamber 3 by the blower 4, external air is sucked through a lower portion of the door 7 according to Bernoulli's equation using a velocity difference of an exhaust air flow and then discharged together with heat discharged from the electronic equipment chamber 3.
However, the related art cooking device has the following problems.
That is, since the door 7 is cooled merely by the natural convection according to the Bernoulli's equation, the door 7 cannot be sufficiently cooled, and if the blowing power of the blower 4 is degraded as the blower 4 is used for a long time, heat discharged from the electronic equipment chamber 3 could flow backward to the cooling passage 7′ of the door 7, much degrading cooling performance of the door 6.
In particular, when pyrolysis cleaning is performed, the temperature inside the cooking chamber 2 is controlled to be increased up to above 450° C. to pyrolyze dirt smudged inside the cooking chamber 2, for which, however, the cooling structure of the door 7 as stated above cannot suitably cope with the high temperature, so the surface temperature of the door 7 is increased up to above 130°.
In addition, when the user opens the door 7 following the cooking or the pyrolysis cleaning, as shown in FIG. 3, the face of the user is bound to be directly exposed to the internal air of the cooking chamber 2. In this case, the internal air of the cooking chamber 2 is in a high temperature and high pressure state, including oil and moisture discharged from a food item therein, making the user feel uncomfortable, and in a worse case, a security problem, for example, the user could be burned, can arise.